When drinking, especially with vodka, never raise your glass from the table alone and drink. It must be done with at least one other person.
When shaking hands, give a firm handshake with your right hand and do not put your left hand in your pocket or anywhere out of sight.
To address an elder stranger, never use second person pronouns (i.e. “you”). You must address them as “sir” or “madam”.
Pierogies are Polish dumplings that usually contain meat, cheese, and potatoes within.

https://www.cia.gov/library/publications/the-world-factbook/geos/pl.html (Majority of information)
http://bit.ly/2flpVTs (City population data)
Wolfram|Alpha (Currency exchange data)
Information accurate to best of ability as of 26 November 2016